The present invention relates to an apparatus and method for permanently closing body vessels such as the utero-tubal junction, uterine isthmus, and fallopian tubes. In particular, this invention is directed to a relatively simple surgical procedure for sterilizing human females which may be performed in the physician""s office.
It is often desired or necessary for medical reasons to permanently close the fallopian tubes of women. The procedures currently proposed for occluding the fallopian tubes to effect sterilization include surgical ligation, occlusion by insertion of a foreign body, and occlusion by scarring in response to severe wounding.
One method for sterilization in females is surgical tubal ligation, a procedure in which the fallopian tubes are tied and cut, or clamped or fused with instruments passed into the pelvic cavity through an incision made through the wall of the abdomen. When done endoscopically, the pelvic cavity must be pneumatically inflated using an inert gas. Tubal ligation done with a laparotomy requires a surgical incision in the abdomen between 6 and 12 centimeters long done under general anesthesia. Currently, when the fallopian tubes are clamped or fused from the outside of the tubes, they must be clamped or fused at two or three different points in order to ensure that the tubes remain closed.
Various wounding techniques have been proposed. Cohen, et al, Method for Tubal Electroligation, U.S. Pat. No. 5,556,396 (Sep. 17, 1996) discloses a method for tubal ligation by providing an electrically energizable electrode to a fallopian tube. The electrode is advanced into the fallopian tube and energized to thermally damage the fallopian tube, thereby causing enough scarring of the fallopian tube to permanently occlude it. In another technique, a sclerosing agent (quinacrine) is injected into the uterus and fallopian tubes to create a permanent closure of the fallopian tubes.
Various plugs have been proposed for occlusion of the fallopian tubes or the utero-tubal junction. One technique involves transcervically injecting a curable elastomeric composition such as silicone into the fallopian tubes in an amount sufficient to fill the portion of the oviduct adjacent the uterus. The elastomeric composition is allowed to solidify to thereby nonsurgically block the tube. Erb, Method and Apparatus for No-Surgical, Reversible Sterilization of Females, U.S. Pat. No. 3,805,767 (Apr. 23, 1974). Others have proposed placement of an occlusive wire or coil within the fallopian tubes to occlude them. Ton, Endoluminal Coil Delivery System Having A Mechanical Release Mechanism, U.S. Pat. No. 5,601,600 (Feb. 11, 1997), proposes placement of a Guglielmi detachable coil (typically used for vascular occlusion) deep within the fallopian tube, past the isthmus. The coil must be delivered into the fallopian tubes with a delivery catheter extending from the uterus into the fallopian tubes.
Several references suggest that the fallopian tube should be damaged to the point of scarring to weld the tubes shut or to enhance retention of a plug. For example, Vancaillie, Transuterine Sterilization Apparatus and Method, U.S. Pat. No. 5,095,917 (Mar. 17, 1992) teaches a method of forming scar tissue in the fallopian tube to occlude the fallopian tube, including application of chemical scarring agents (tetracycline hydrochloride) or application of high frequency current to the fallopian tubes. The goal is to cause an immediate inflammatory reaction, including edema, arrival of white blood cells, proliferation of fibroblasts and connective tissue, and arrival of macrophages, and also to cause the subsequent healing process which leads to the formation of scar tissue in the damaged area. Lessen, Surgical Method and Electrode Therefor, U.S. Pat. No. 3,858,586 (Jan. 7, 1975) teaches the scarification of the fallopian tubes with the application of RF energy, without placement of a plug afterward, under the theory that the resulting scarring would be sufficient to seal the fallopian tubes. Both the type of injury used to initiate a lesion in the ostium/isthmus/fallopian tube and the nature of the plug material dictates the type of wound healing response that occurs. If high power is used to create the lesion, the biological response of the body will follow a typical inflammatory response and lead to creation of scar tissue.
If the plug material has an architecture, chemistry and/or pore size (smooth, non-porous materials, for example) that induces a foreign body response to the material, this will encourage the formation of scar tissue and a fibrous capsule which surrounds the plug. The foreign body response consists primarily of fibroblasts attraction to the area (including fibroblast insinuation into the plug material, if possible) and the resultant formation of connective matrix with few vascular structures. The foreign body response has also been described as xe2x80x9cscarxe2x80x9d formation. The cells that comprise this foreign body response can differentiate into myofibroblasts that are capable of contracting around the material and either cause the material to distort or fracture, or in the fallopian tube, dislodge the implant. The combination of the myofibroblastic contractions, peristalic movement of the tube, tubal contractions, and ciliated epithelium create a combined force capable of expulsing the material from the tube.
If the plug is inserted into a fallopian tube without the concomitant disruption of the epithelial cell lining, expulsion of the plug will usually result. The epithelial lining of the fallopian tube functions to protect the underlying layers from infiltration and infection by foreign substances and infectious agents. In the same way, few cells will traverse the epithelial lining to enter the lumen of the fallopian tube, where the plug resides. Thus, implanting a plug in an intact tube results in little, if any, infiltration unto the plug material. Instead, it is likely that a non-infiltrated large pore plug would become a receptacle for necrotic debris shed within the fallopian tube. This could result in higher contamination and infection of the plug matrix. Additionally, the lack of ingrowth would result in less anchoring of the plug matrix, so the expulsion forces present within the fallopian tube could dislodge and expulse the plug. Thus, retention of an intact epithelial layer is not desired, and the epithelial cell layer must be destroyed or disrupted to eliminate the physical barrier to infiltrating cells. After this has occurred, a porous material can be placed into the denuded area, and a wound healing response can follow. Implanting porous materials into a fallopian tube that has an intact epithelial lining does not allow ingrowth into the material, as part of the epithelial cell lining""s function is to act as a physical barrier to infectious agents and cellular infiltrate.
Our prior patent application, Harrington et al, Method And Apparatus For Tubal Occlusion, U.S. application Ser. No. 09/063,119, (filed May 20, 1998) (the disclosure of which is incorporated herein by reference) illustrates a method blocking off the fallopian tubes by placing a plug in the ostium or cornu of the uterus leading into the fallopian tubes. An exemplary embodiment discussed in our prior application was the application of heat to damage the tissue of the ostium and place a plug into the ostium which, was secured into the ostium by the inflammation of the ostium caused by the thermal injury. The proposed plug comprised a foamed material which permitted the ingrowth of tissue into the plug.
The method and devices described below provide for occlusion of the fallopian tubes of a woman. The method involves thermally damaging the lining of the utero-tubal junction with relatively low power energy, followed by placement of a reticulated foam plug. The power applied to the lining of the ostium utero-tubal junction is limited to avoid thermal damage to the deep tissue in the area, yet thoroughly damages the superficial tissue. Placement of the plug having suitable flexibility, architecture and foam pore size into the lightly damaged utero-tubal junction encourages the healing tissue to grow into the plug. The tissue that grows into the plug is vascularized to a normal extent, and appears in cross section as an xe2x80x9corganoidxe2x80x9d mass. Ingrowth of healthy vascularized tissue into the plug prevents or discourages formation of scar tissue around the plug. This minimizes the likelihood of ejection of the plug, and also minimizes the probability that expected re-growth of epithelial tissue in the damaged portion of the utero-tubal junction will continue to the point where fistulation of the occlusion occurs. In another embodiment, the plug comprises a foam having suitable flexibility, architecture and a relatively small foam pore size that does not encourage vascularized tissue ingrowth. This plug is implanted into the lightly damaged utero-tubal junction and encourages formation of a vascularized capsule around the plug. The presence of this vascularized capsule limits the patient""s foreign body response, so that the capsule does not constrict around the plug. No substantial ingrowth occurs, although macrophages will most likely infiltrate the plug.
Also presented is a catheter designed for wounding the epithelial layer of the utero-tubal junction, and a method of using the catheter to form a long yet shallow lesion in the utero-tubal junction.